Polyurethane foam based biofilter media for toluene removal

Polyurethane foam medium was manufactured and analyzed to determine its sui tability as a solid support medium for use in gas-phase biofilters. Physica l and chemical studies were conducted to determine the medium's characteris tics. The medium's ability to support an active biofilm capable of degradin g volatile organic compounds was assessed using a laboratory scale biofilte r fed a model waste stream containing toluene for more than 250 days with e mpty bed residence times (EBRTs) ranging from two to four minutes. Results are presented that show how a polyurethane foam medium with high porosity, suitable pore size, low density, and an ability to sorb water was able to r emove over 99% of the influent toluene when fed at a concentration of 200 p pm(v). An operating strategy is described which effectively prevented two p roblems common to conventionally operated biofilter systems: nutrient limit ations and biosolid accumulation.